Arriving on the market in 1976, the Apple I featured a 1MHz processor and 4KB of memory, and was sold as a lone circuit board. Users were required to add a display, casing and peripherals themselves.

Cologne-based auctioneer Breker is expecting the computer to raise between €200,000 and €300,000 (£168,000 and £253,000) when it goes under the hammer later this month.

Other items to be sold at the rare computer auction include a working model of Apple's Lisa-I PC, a Busicom 141-PF calculator, an Altair 8800, and a working version of history's first mechanical calculator, the Pascaline.